The Sacramento River is the longest river in the U.S. state of California. Starting at the confluence of the South Fork and Middle Fork Sacramento River, near Mount Shasta in the Cascade Range, the Sacramento flows south for 447 miles (719 km) , through the northern Central Valley of California, between the Pacific Coast Range and the Sierra Nevada.Not far downstream from its confluence with the American River, the Sacramento River joins the San Joaquin River in the Sacramento River Delta, which empties into Suisun Bay, the northern arm of San Francisco Bay.The chief tributaries of the Sacramento River are the Pit, Feather, McCloud and American rivers. The Pit River is the longest of these, but the Feather and American rivers carry larger volumes of water. The Pit River's watershed formerly included Goose Lake, and still does during rare periods of high water.